Heat employing copying apparatus



March 22, 1966 a. CRANSKENS HEAT EMPLOYING COPYING APPARATUS Filed Oct. 4, 1963 4 Sheets-Sheet 1 INVENI'OR @5026 CRANSKENS AGENT March 22, 1966 G. CRANSKENS HEAT EMPLOYING COPYING APPARATUS 4 Sheets-Sheet 2 Filed 0612. 4, 1963 WViA/IO/P GEORG CRANSKENS AGENI' 4 Sheets-Sheet 5 Filed Oct. 4, 1963 m mum m yz/vrae GEORG CRANSKENS March 22, 1966 c;. CRANSKENS 3,242,316

HEAT EMPLOYING COPYING APPARATUS Filed 001:. 4, 1965 4 Sheets-Sheet 4.

Wyn/70F GEORG CEANSKENS AGEN'E United States Patent 3,242,316 HEAT EMPLOYING COPYING APPARATUS Georg Cranskens, Wedel im. Holstein, Germany, assignor to Lumoprint Zindler KG, Hamburg, Germany Filed Oct. 4, 1963, Ser. No. 314,050 Claims priority, application Germany, Oct. 13, 1962, L 43,199 12 Claims. (Cl. 219-471) This invention relates to a heat employing copying apparatus comprising a rotatable, heated drum with good heat absorbing characteristics, and a heat source accommodated within this drum which is driven for guiding and advancing the copying materials and is looped at least partly by belt means made of flexible, heat resisting and good heat conducting material, advantageously forming a good heat storage, and serving to guide and urge the copying material towards and against the drum, a switch being provided to disconnect the heat source in response to the generated temperature.

Such apparatuses are known, for example, for thermodiazo methods and may also be employed in thermodiifusion methods which, for example, are using copying material having a layer in which substances are provided which, under the influence of heat, will generate moisture allowing the diffusion of certain substances of this layer into the reaction layer of another material.

In such apparatuses one problem is to be seen in that during short or long operating periods a uniform tempera ture kept as far as possible within narrow limits must be generated along the guide path of the copying material. To this end known apparatuses employ heat sensers in form of thermostats the sensers of which are for example sliding on the drum. This causes inaccuracies due to the additional frictional heat and wear. It is also known to sense the air temperature but, even if in this case a heat sensitive resistance in connection with an amplifier circuit in used, inaccurate switching ranges are obtained, since the air temperature adjacent the drum will not change as rapidly as the drum temperature proper. It is intended that in this case the expression drum temperature also relates to the temperature of the direct guide elements for the copying material.

If thermostats are used which are rotating with rotating parts special sliding contacts must be proivded for the thermostat feed line and also for the heat source. vSuch sliding contacts as a rule have irregular and changing transfer resistances which are also influenced by wear and fouling as well as by fatigue of material of possibly used resilient elements so that also in this case no particular accuracy is obtainable.

Generally these known embodiments operate indirectly with special heat sensers whereby also disadvantageous influences arise.

According to the invention these drawbacks of the known embodiments are overcome in that an element being influenced by heat operatively rotates along the guide path of the copying material cooperates directly with the switch for the heat source by switching it on or off by the heat expansion of said element in dependence on the temperature.

As an operating rotating element preferably not a special element for sensing the heat is provided, but a structural element existing per se for the operation of the apparatus is used. The element operatively rotating along or within the guide path of the copying material is in this adapted to directly transmit the prevailing temperature to the switch.

According to a preferred embodiment of the invention the drum is rotatably supported by at least one endless belt guided over three rollers in which at least one of said rollers is made of a material having a relatively 3 ,242,3 l6 Patented Mar.- 22,1966

great heat expansion capacity said latter roller cooperatmg with a switch fixedly arranged relative to said roller.

According to another advantageous embodiment the actuatlng member of the switch is associated with said drum WhlCh according to the heat expansion of said drum W111 close or open said switch for the heat source. In this a referred embodiment provides that the rotating member is a x1ally non-shiftably guided at one face while the opposite face cooperates a rotating rigid part said roller or drum is used for example in this case.

According to a further advantageous embodiment of the lnvention rigid parts, the longitudinal heat expansion of which causing the switching of the heat source, are on the one hand mounted on a first reference structure and on the other hand movable relative to a second reference structure which is carrying the switch, said reference structures being held rigidly relative to each other by means of a substantially heat indifferent reference element, preferably an Invar rod. In this a considerable reaction accuracy is obtained.

According to another embodiment of the invention a heat sensing endless belt consisting, for example, of metal is guided over a tensioning roller and in parallel relation to said at least one belt means, said tensioning roller cooperatingwith said switch opening or closing it in dependence on a pivoting movement of said tensioning roller.

According to still another embodiment of the invention a guide roller for said at least one belt means of flexible material is resiliently supported. This resilient support has a movement direction in a sense to tension said belt means. In this a sensing lever is provided transmitting the position of said guide roller in dependence on the heat expansion of said at least one belt means to the switch thereby switching said heat source off or on.

In heat employing developing apparatuses drums of meta1 with good heat conductivity are well known. The invention includes that such a drum is thin-walled preferably made of copper and has a small specific heat.

According to another embodiment the drum consists of glass. i It is known that a black coating readily absorbs heat of the heat source. While it has been proposed already to provide such a coating on the innersurface of said drum the invention provides that this coating is arranged on the outer surface of said glass drum, whereby the heat absorbing body is brought directly onto the guide path of the copying material. Preferably the inner surface of the drum is roughened which ensures an especially. good heat absorption. Preferably the glass drum may also be roughened on its outer surface.

According to the preferred embodiment of the invention the at least one belt means of flexible material has a good heat absorbing character and is black in colour. This is especially important according to the invention if this belt means is used for transmitting heat to a rolleroperating as control means for said switch. The belt means, for example, is made of synthetic rubber or a corresponding synthetic material such as, for example polytetrafluoroethylene which is an advantageous manner may also be arranged as a plastic material coating on said drum. This material is advantageous in that it does not stick to the copies which may possibly be the case in cer high amperages.

with said actuating member. As.

The invention is followingly described with reference to some embodiments shown in the accompanying drawings, in which:

FIG. 1 is a front view of an apparatus according to the invention with partly broken away front plate;

FIG. 2 is a sectional side view of the apparatus as viewed along line IIII in FIG. 1;

FIG. 3 is a top view of the apparatus shown in FIG. 1 with the upper housing part cut away in which part of the air guide channel is broken away;

FIG. 4 is a schematic side view of another embodiment according to the invention;

FIG. 5 is a schematic view of the drive arrangement including one embodiment of the functional means according to the invention; and

FIG. 6 is a part view of the drive arrangement according to FIG. 5, however, with another arrangement of the functional means according to the invention.

The apparatus shown in FIGURES l-3 comprises a housing 1 the rear wall of which being removable. The front wall is provided with inlet openings 2 and 3, each of which being subdivided into two sections by an inwardly diverging guide element 4, or 5 respectively. The guide elements 4, 5 are mounted to lateral structure walls 8, 9. In the rear of each opening a processing station is arranged. The invention shows an apparatus including exposure means 6 and heating means 7 both being constructed similarly.

Three rollers 10, 11, 12, or 13, 14, respectively, are provided for processing each station and are rotatably supported in the associated lateral structure walls 8, 9. Particularly the rollers 10, 13 are provided with gears 16', 17 meshing with corresponding gears 18, 19 of a drive motor transmission unit generally denominated with 20.

At least one endless belt 21, 22 is guided over the rollers 10, 11, 12, or 13, 14, 15 respectively, and at the same time is looped around a drum 23, or 24 respectively, holding it in contacting and rotating engagement against the rollers 11, 12, or 14, 15 respectively. Instead of the at least one endless belt 21, 22 a plurality of belts arranged and guided in parallel relation may be used. In the illustrated embodiment the rollers are journalled stationarily using a belt extending over the entire width of the arrangement providing the required tension. It is also possible to journal the rollers 10, 13 resiliently thereby forming tensioning rollers. In FIG. 2 springs 55, 56 are shown pressing against the bearings of the rollers 10, 13 for tcnsioning the belts 21, 22. These springs engage with their opposite ends the structure walls 8, 9.

In the embodiment of the processing station 6 the drum 24 forming the exposure source surrounds a radiation source 25 for visible light. Such an embodiment of an exposure device is known per se. The drum consists, for example, of glass. The light source 25 may be supported by contacts 57, 58 mounted on the structure walls 8, 9. The light source may, for example be formed by a luminous-discharge tube; its connection is shown in FIGURES 5 and 6.

The drum 23 preferably consists of thin walled copper but may also be made of glass. In the latter case it advantageously carries a black layer on its outer surface. A heat radiating source 26 is arranged within the drum Which preferably extends through the structure walls 8, 9 and is secured to supply terminals. The heat radiating source is formed, for example, as a tube-like infra red radiator, preferably a quartz glass radiator with a Wolfram coil in vacuum or inert gas. This has the advantage of a short heating-up time after switching-on and little heating after switching-off, whereby it is not necessary to wait a relatively long time until the apparatus is ready for operation, and furtherinore it is possible to operate with close temperature tolerances. Thus it is possible to obtain a heating-up time of less than one minute.

The drum 23 may advantageously be provided with an antlstick layer consisting, for example, of a plastic ma- 4 terial, preferably of polytetrafluorethylen which prevents that the softened copies will stick to the drum.

A so-called microswitch 29 is mounted on the structure wall 8 and comprises an actuating member 30 which cooperates with a pivoting lever 31. This pivoting lever carries an adjustable stop member 32 for the actuating member 30. As shown in FIG. 1 the pivoting lever is supported on an axle 33 vertically extending relative to the plane of the drawing. This axle 33 may, for example, be mounted on a bracket 59 of the structure wall 8. At its other end the pivoting lever carries a spring support 34 urged by a tension spring 35 towards the structure wall 8. With the other end the tension spring 35 is anchored to the structure wall 8. Between the axle 33 and the operating zone of the actuating member 30 a pin 36 is acting upon the pivoting lever, said pin being rigidly mounted on and projects from the roller 11 and is rotatably journalled in the bearing 38. The latter is arranged in the'structure wall 8 and mounted in a manner known per se. It is to be noted that the hub 37 terminates in spaced relation to the bearing 38 so that the pin 36 is axially reciprocating within the opening of the bearing in dependence on the longitudinal heat expansion of the roller 11. The hub 37 is, for example, arranged at one side of the roller 11. The stub-like projecting hub 37 may, for example, also be arranged rotatably and movably in axial direction, and may carry the pin 36 at its end extending through the structure wall 8.

A pin 39 is also extending from the face at the other side of the roller 11 extending through a bearing 40 mounted on the structure wall 9. However, this hearing is at the same time an axial thrust bearing forming an abutment for the face at this side, for example the hub. Thus the longitudinal heat expansion of the roller 11 is only effective to displace the pin 36 for moving the pivoting lever 31.

Directly above the roller 11 the structure walls 8, 9 are rigidly connected by a rod 41 consisting of a material having a small coeflicient of expansion. This rod is at both ends adjustably secured by screws. If the rod is made, for example, of Invar steel its longitudinal expan sion coefficient is 0.9 10- If the roller 11, for example, is made of aluminium its longitudinal expansion coefficient is 23 10- which shows that even under uniform heated conditions there would be a difference which would allow switching. However, the rod 41 remains by far colder than the roller 11, or possibly the drum 23 since, for example, the heat is directly transmitted to,

the roller 11 via the belt 21 with good heat storage capacity. Under these conditions extremely close temperature ranges may be switched, not only in dependence on the drum, of which the longitudinal expansion could also be used for switching, but also particularly in dependence on the roller '11. The belt, which constantly has a close contact with the drum as well as with the guide roller during operation of the apparatus provides a rigid heat coupling which is substantially independent on ambient influences. By using the belt 21 as a coupling means the advantage is obtained at the same time that also the belt temperature is included in the measurement since the copying process is not only dependent on the drum temperature but also on the belt temperature.

A tangential ventilator 42 is associated with the processing stations driven by a motor-transmission unit 20 venting the processing stations through an air guide channel 43 and an opening 54 in the rear Wall.

Within the apparatus connection units .for the heat radiator and for the light radiation sounce 25 are provided. For the latter, for example, a resistance 44 which is connectible and/ or adjustable by a hand lever 45.

It is to be understood that also additional rods corresponding to the rod 41 -may be arranged for providing a definite spacing between the structure walls 8, 9. However, practice has shown that, if for example the roller 1 1 is used for controlling the heat, the arrangement of only one rod 41 is suflicient to obtain a high switching accuracy.

In FIG. 4 another embodiment is illustrated which uses, corresponding to the arrangement shown in the other figures, a drum 23, the guide rollers 1'1, 12', and at least one belt 21 guided over the rollers for supporting and guiding the drum within which a heat radiator 26' is arranged. An endless steel rope 46 is guided in parallel relation to the belt 21'. At one :location the steel rope 46 is guided out of the path of movement of the belt or belts 21 and guided over a tensioning roller 47. The tensioning roller is carried by a lever pivotally supported on one of the structure walls 8 or 9 and subjected to the action of a spring 61 the opposite end of which being secured to the structure wall 8 or 9. This spring ,61 tends to pivot the lever in the direction in dicated by the arrow 49. An actuating arm 50 is pivotally connected to the lever with its one end while its other end is suspended by a spring 51 on one of the structure walls. Between its ends the arm carries an adjustable abutment 52 engageable by an actuating member 30' of a micro switch 29' also mounted on the associated structure wall. The spring 51 resiliently urges the arm 50 against the actuating member 30.

FIG. 5 shows an energy source '62 to which the circuits are connected possibly via a switch formed by a relay. For example, the light source 25 rotating within the drum 24 is connected via an adjustable resistance denominated like in the other figures with 46. Further, the drive motor transmission unit 20 is included in the circuit which also drives the drum 23 for the heat radiator 26, shown in dashed lines via the transmission 64, the drum 24 and the transmission 65. The heat radiator is connected by the switch 66 corresponding to the micro switch 29 of the above description. Further, the structure wall 8, 9' and the roller 10 are shown, and it will be noted that the roller v10 with its hub extension, or pin 36 for actuating the switch 66 is extending axially movably through the structure wall 8, in which the pin 36 is cooperating with the switch 26 which is subjected to the action of the spring 67' functionally corresponding to the spring 35 shown in FIG. 1. The heat conduction from the heating means 23, 26 to the roller 10 is schematically shown by the wall section 68.

It is to be understood that the rod 41 is arranged [between the structure walls 8, 9 in the dot and dashed shown manner if the mechanical parts of the switch 66 are mounted on the structure wall 8.

In FIG. 6 the drum 23' and the roller 10 are shown 90 shifted in a front view. Like parts with those shown in FIG. 5 are denominated with like reference numerals. It will be noted that the steel rope 46 shown in FIG. 4 is also arranged between the drum and the roller 10. The tension of the steel rope is sensed by the sensing roller 69 subjected to the action of a spring 35. This sensing roller corresponds to the sensing roller 47 shown in FIG. 4 and is connected \by a guided connecting member 70 with the switch 66.

What I claimed is:

1. In a thermal copying apparatus comprising a housing; a drum of good heat-absorption characteristic rotatably and drivably arranged within said housing; a heat source arranged within said drum and connectable to a source of energy therefore; drive means for rotating said drum; flexible-belt guide means at least partly looped around said drum for guiding a copy material therearound; said guide means consisting of heat-resisting material with good heat-conducting character and constituting a heat-storage reservoir; connecting means between said source of energy and said heat source including a switch for controlling said heat source in dependence on the generated temperature, said drum and said guide means forming at least one section of a guide path for said copy material, the improvement which comprises a heat-expendable element arranged at said section' of the guide path such that said element is heated to the temperature of said section of the guide path, link means interconnecting said element and said switch whereby said switch is actuated in dependence on the temperature by the heat expansion of said element, said element being arranged to rotate correspondingly with the movement of said copy material and being associated with said drum in a manner allowing heat to be trans ferred from said drum to said element, and three rollers are journalled within said housing and cooperating with said drum, said guide means being endless and being guided over said roller-s, said guide means being looped about a substantial part of the periphery of said drum, at least one of said rollers forming said rotating elements, said switch being disposed stationarily with respect to said one of said rollers and cooperates with said one of said rollers via said link means.

2. An apparatus according to claim 1, wherein said one roller is journalled at one side in one wall of said housing by a thrust bearing in an axially non-shiftable manner, a hub being provided at the opposite side which is journalled in another wall of said structure in an axially shiftable manner, said hub cooperating with an actuating member of said switch.

3. An apparatus according to claim 2, in which said walls form a reference structure carrying said switch, at least one substantially heat-indifferent reference element being provided between said structure walls of said reference structure for rigidly maintaining the positions of said walls of said reference structure relative to each other.

4. An apparatus according to claim 3, in which said reference element is formed by a rod of Invar steel ar ranged between said walls.

5. In a thermal copying apparatus comprising a housing; a drum of good heat-absorption characteristic rotatably and drivably arranged within said housing; a heat source arranged within said drum and connectable to a source of energy therefor; drive-means for rotating said drum; flexible-belt guide means at least partly looped around said drum for guiding a copy material therearound, said guide means consisting of heat-resisting material with good heat-conducting character and constituting a heat-storage reservoir; connecting means between said source of energy and said heat source including a switch for controlling said heat source in dependence on the generated temperature, said drum and said guide means forming at least one section of a guide path for said copy material, the improvement which comprises a heat-expandable element arranged at said section of the guide path such that said element is heated to the temperature of said section of the guide path, link means interconnecting said element and said switch whereby said switch is actuated in dependence on the temperature by the heat expansion of said element, said element being arranged to rotate correspondingly with the movement of said copy material and being associated with said drum in a manner allowing heat to be transferred from said drum to said element, said element being formed by an endless heat-sensitive belt, a guide roller provided within said housing in parallel spaced relation to said drum, a tensioning roller disposed between said guide roller and said drum and acting upon said belt, and a carrier for said tensioning roller movably supported by structure members rotatably supporting said drum and said guide roller, resilient means being provided between said carrier and said structure members for urging said tensioning roller against said belt, said link means being provided between said carrier and said switch for switching the latter in dependence on the heat expansion of said belt and the consequent movement of said carrier.

6. In a thermal copying apparatus comprising a housing; a drum of good heat-absorption characteristic rotatably and drivably arranged within said housing; a heat source arranged within said drum and connectable to a source of energy therefor; drive means for rotating said drum; flexible-belt guide means at least partly looped around said drum for guiding a copy material therearound; said guide means consisting of heat-resisting material with good heat-conducting character and constituting a heat-storage reservoir; connecting means between said source of energy and said heat source including a switch for controlling said heat source in dependence on the generated temperature, said drum and said guide means forming at least one section of a guide path for said copy material, the improvement which comprises a heat-expandable element arranged at said section of the guide path such that said element is heated to the temperature of said section of the guide path, link means interconnecting said element and said switch whereby said switch is actuated in dependence on the temperature by the heat expansion of said element, said element being arranged to rotate correspondingly with the movement of said copy material and being associated with said drum in a manner allowing heat to be transferred from said drum to said element, a guide roller for said flexible-belt guide means cooperating with said drum and rotatably supported in parallel spaced relation to said drum, bearing means in said housing, a structure carrying said bearing means and also serving to rotatably support said drum, said bearing means allowing said guide roller to move axially relative to said structure, resilient means acting upon said guide roller to tension said guide means, and a sensing lever movably arranged within said structure cooperating with said guide roller, said link means being provided between said sensing lever and said switch to actuate the latter in dependence on an axial movement of said guide roller.

7. An apparatus according to claim 1, in which said drum is formed by a thinwalled metal having a low specific heat.

8. An apparatus according to claim 1, in which said drum is formed of glass.

9. An apparatus according to claim 8, in which a black coating is provided on the outside surface of said glass drum.

10. An apparatus according to claim 9, in which the inner surface of said drum is roughened.

11. An apparatus according to claim 7, in which the inner surface of said drum is roughened.

12. In a thermal-copying apparatus, comprising, in

combination:

(a) a housing;

(b) a heat-absorbing drum for entrainment of a thermally treatable copying material along an arcuate transport path, journaled in said housing;

(c) drive means for rotating said drum;

(d) a flexible belt looped around part of the periphery of said drum and entrainable thereby for guiding said copy material along said path;

(e) a source of thermal energy along said path;

(f) switch means in saidhousing for controlling said source in dependence upon the heating eifect produced thereby;

(g) a thermally expandable element in said housing rotatably entrained at the peripheral speed of said drum for generating movement in dependence upon the heating eifect of said source; and

(h) link means connecting said element with said switch means.

References Cited by the Examiner UNITED STATES PATENTS 1,594,158 7/1926 Else 219-512 1,612,270 12/1926 Duffie 39 3,027,285 3/1962 Eisner et a1. 2l9470 RICHARD M. WOOD, Primary Examiner.

L. H. BENDER, Assistant Examiner. 

12. IN A THERMAL-COPYING APPARATUS, COMPRISING, IN COMBINATION: (A) A HOUSING; (B) A HEAT-ABSORBING DRUM FOR ENTRAINMENT OF A THERMALLY TREATABLE COPYING MATERIAL ALONG A ARCUATE TRANSPORT PATH, JOURNALED IN SAID HOUSING; (C) DRIVE MEANS FOR ROTATING SAID DRUM; (D) A FLEXIBLE BELT LOOPED AROUND PART OF THE PERIPHERY OF SAID DRUM AND ENTRAINABLE THEREBY FOR GUIDING SAID COPY OF THERMAL ENERGY ALONG SAID PATH; (E) A SOURCE OF THERMAL ENERGY ALONG SAID PATH; (F) SWITCH MEANS IN SAID HOUSING FOR CONTROLLING SAID SOURCE IN DEPENDENCE UPON THE HEATING EFFECT PRODUCED THEREBY; (G) A THERMALLY EXPANDABLE ELEMENT IN SAID HOUSING ROTATABLY ENTRAINED AT THE PERIPHERAL SPEED OF SAID DRUM FOR GENERATING MOVEMENT IN DEPENDENCE UPON THE HEATING EFFECT OF SAID SOURCE; AND (H) LINK MEANS CONNECTING SAID ELEMENT WITH SAID SWITCH MEANS. 